Mks Instruments, Inc.

Analog Devices,inc.

Invensense, Inc.

Stephen F Bart

Lei Gu

Roger T Howe

Richard S Payne

Paul D Lucas

Nishit Goel

Omid Oliaei

Srinivas Tadigadapa

Ole Wenzel

Philip W Sullivan

Phillip W Sullivan

The present invention relates to an incremental analog to digital converter incorporating noise shaping and residual error quantization. In one embodiment, a circuit includes an incremental analog to digital converter, comprising a loop filter that filters an analog input signal in response to receiving a reset signal, resulting in a filtered analog input signal, and a successive approximation register (SAR) quantizer, coupled with the filtered analog input signal, that converts the filtered analog input signal to an intermediate digitized output of a first resolution based on a reference voltage, wherein the SAR quantizer comprises a feedback loop that shapes quantization noise generated by the SAR quantizer as a result of converting the filtered analog input signal; and a digital filter, coupled with the intermediate digitized output, that generates a digitized output signal of a second resolution, greater than the first resolution, by digitally filtering the intermediate digitized output.

Incremental analog to digital converter incorporating noise shaping and residual error quantization

A gas sensor may include a plurality of elements that are responsive to particular gases based at least in part on the temperature of the temperature sensitive element. A first of the elements may be a gas detection element heated to a temperature at which it is responsive to a gas of interest. A plurality of additional elements may be configured in a reference element network and heated to a temperature at which they are not responsive to the gas of interest but are instead responsive to other effects such as humidity. The reference element network output may be used to remove the other effects (e.g., humidity) from the gas detection element output.

Humidity correction method in thermistor based gas sensing platform

A pressure sensor may measure gas or liquid pressure. A chamber may have an inlet that receives the gas or liquid. A flexible diaphragm may be within the chamber that has a surface exposed to the gas or liquid after it flows through the inlet. A pressure sensor system may sense changes in the flexible diaphragm caused by changes in the pressure of the gas or liquid. A pressure-insensitive sensor system may sense changes in the flexible diaphragm that are not caused by changes in the pressure of the gas or liquid. The pressure-insensitive sensor system may be insensitive to changes in the flexible diaphragm caused by changes in the pressure of the gas or liquid.

Pressure sensor with real time health monitoring and compensation

A pressure sensor includes a piezoelectric substrate having a generally planar structure and an anchor location fixing the piezoelectric substrate at the periphery of the planar structure of the piezoelectric substrate. The planar structure of the piezoelectric substrate has a first region having a first characteristic thickness adjacent to the anchor location, and a second region have a second characteristic thickness at a middle region of the substrate. The second characteristic thickness is less than the first characteristic thickness such that the planar structure in the second region is displaced relative to the neutral axis of the planar structure such that while undergoing bending the second region has either mostly compressive or mostly tensile stress.

Micromachined bulk acoustic wave resonator pressure sensor

A pressure sensor system may sense the pressure of a gas or liquid. The system may include a housing that has an entry port for the gas or liquid; a pressure sensor within the housing; and a baffle positioned between the entry port and the pressure sensor. The baffle may have one or more inlets oriented to receive gas or liquid that enters the entry port; one or more outlets oriented to deliver the received gas or liquid to the pressure sensor; and one or more sealed flow channels that prevent the gas or liquid from escaping from the baffle, other than through the one or more outlets. At least one of the outlets may be located within no more than one millimeter of a location on the pressure sensor. The pressure sensor and baffle may be made at the same time during a process of depositing, pattering, etching, wafer bonding, and/or wafer thinning a series of layers using microelectromechanical systems (MEMS) technology.

MEMS pressure sensors with integrated baffles

Stress relief structures and methods that can be applied to MEMS sensors requiring a hermetic seal and that can be simply manufactured are disclosed. The system includes a sensor having a first surface and a second surface, the second surface being disposed away from the first surface, the second surface also being disposed away from a package surface and located between the first surface and the package surface, a number of support members, each support member extending from the second surface to the package surface, the support members being disposed on and operatively connected to only a portion of the second surface. The support member are configured to reduce stress produced by package-sensor interaction.

Stress relief MEMS structure and package

Micro-Pirani gauge vacuum gauges are described that use low-thermal conductivity support elements. A micro-Pirani gauge or vacuum sensor can include a heating element operative to heat a gas and to produce a signal corresponding to the pressure of the gas; a platform configured to receive the heating element, with the platform having a first coefficient of thermal conductivity; and a support element connected to a substrate and configured to support the platform with the heating element within an aperture disposed in the substrate, with the support element having a second coefficient of thermal conductivity, where the second coefficient of thermal conductivity is less than the first coefficient of thermal conductivity. Multimode pressure sensing including a micro-Pirani gauge are also described.

Micro-Pirani vacuum gauges

A method and apparatus for providing a sub-ground plane for a micromachined device. The sub-ground plane is formed in or on the substrate. Above the sub-ground plane is a dielectric and then a discontinuous conductive layer used for interconnects for parts of the micromachined device. A movable microstructure is suspended above the interconnect layer. A conductive layer can be suspended above the movable microstructure. In one embodiment, the sub-ground plane is diffused into the substrate or a well in the substrate, and is of an opposite type from the type of silicon into which it is diffused. Alternatively, the sub-ground plane is formed from a conductive layer, deposited over the substrate before the layer used for interconnects.

Method of making a sub-ground plane for a micromachined device

Sub-ground plane for micromachined device

A micromachined force sensor containing separate sensing and actuator structures. A member is suspended above the substrate so that it is movable along an axis in response to a force. The member includes a set of parallel sense fingers and a separate set of parallel force fingers. The sense fingers are positioned between fingers of two sense plates, to form a first differential capacitor, whose capacitance changes when the member moves in response to a force along the axis. The change in capacitance induces a sense signal on the member, which permits the measurement of the magnitude and duration of the force. The force fingers are positioned between fingers of two actuator plates, to form a second differential capacitor. The sense signal can be used to provide feedback to the second differential capacitor to generate different electrostatic forces between the force fingers and the two actuator plates, to offset the force applied along the preferred axis. Limit stops limit the movement of the member to less than the distance between the electrodes of the differential capacitors, to prevent contact between the electrodes. Additional fingers be positioned around the differential capacitors to minimize parasitic capacitances.

Growing community of inventors

Newton, MA, United States of America

Stephen F Bart